By Dr. Stan Trout | Spontaneous Materials
A recent consulting assignment and April 15, which is tax day in the US, reminded me of a fundamental truth in the world of permanent magnets.
On the day that Federal income tax returns are due, it is not unusual to see a flurry of activity from some people, as they desperately finish their returns. In the days when I used to spend a lot of time in public libraries, there would always be a few tables occupied by forlorn people with their entire financial life laid out in front of them. They did not look like they were having fun. One TV news report I heard this year mentioned that last minute filers frequently make more mistakes on their returns than the rest of us. I don’t think that observation comes as a surprise to anyone.
An analogous thing that happens in the world of permanent magnets is that occasionally people will think about the magnet last, after everything else in the design has been fixed and specified. They hope that a small and inconsequential item like a permanent magnet will neatly fit in the space they provided for it and do just what they expect it to do. Of course, this is a naïve mistake, and things may not work out as anticipated.
Making a device work properly when the size, position or material have already been decided can be an impossible task, because they are frequently chosen incorrectly. When I worked for magnet companies, this type of situation was always extremely frustrating because there could be no business without a working device, so there was a lot of pressure to make the device work, even poorly. As a consultant working at an hourly rate or on retainer, I am permitted to be a bit calmer in these situations, but still wonder why people wait so long to engineer perhaps the most important component in their device. I guess it is a lesson each person needs to learn, at least once.
To repeat an old truth regarding permanent magnets, consider the magnet early in the design process and talk to experienced people, who can help you make good choices. You will guarantee the best possible outcome.
About the Author
Dr. Stan Trout has more than 35 years’ experience in the permanent magnet and rare earth industries. Dr. Trout has a B.S. in Physics from Lafayette College and a Ph.D. in Metallurgy and Materials Science from the University of Pennsylvania. Stan is a contributing columnist for Magnetics Business & Technology magazine. Spontaneous Materials, his consultancy, provides practical solutions in magnetic materials, the rare earths, technical training and technical writing. He can be reached at strout@ieee.org.
